Sewing machine



Jan 6, 1931. A. F. cARLsoN SEWING MACHINE Original Filed Sept. 24 1928lnvenTon Axel F Carlson Patented den. 6, 1931 enrich Alf-1E1 F. CARLSON,OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOB TO THE EJIECE BUT-361T HGLEMAOHZNE QGMPANY, OF BQSTON, MASSACHUSETTS, A CORPORATION OF MAINESEVJ'ING MACHINE Application filed. September 24;, 1928, Serial No.307,948. Renewed May 28, 1980.

lhis invention relates to two-thread sewirg machines of that type whichare adapted to sew a short seam and then come to and which are alsoprovided with means for cutting the under thread close to the work atend of the'sewing operation. One of the objects of the present inventionis to nrovide a novel means for holding the cutond of the under threaduntil the next sewing operation has begun, the thread-holdmo; meansbeing constructed so as to hold the under thread in proper position toensure the correct formation of the first stitch upon the beginning ofthe next sewing operation.

The invention is herein illustrated as it might he embodied in a machineof the type shown in my cc-pending application Serial No. 162 890, filedJanuary 22nd, 192. The sewing machine illustrated in tion is designedfor sewing huttonholes and the devices by which the under thread ismanipulated are carried by a turret which rotatably mounted beneath thework and which has a rotative movement at each end of the huttonhole.The turret in turn is prov vided with a threat plate having a sewingopening in which the upper needle operates and through which the underthread-is led. in accordance with my presentinvention the throat plateis provided with a thread retaining notch so situated that when theturret'is rotated at the end of the sewing op eration the length ofunder thread which passes tl'irough the sewing; opening to the work willbe drawn into the notch. and thereby held.

The thread-cutting mechanism cuts the under thri-wul between the throatplate and the work and by means of my invention the cut ei'id thus heldin proper position to en sure thit it will be properly concatenated withthe upper thread during the iirststitchtorming operati n the beginningof the next seam. V

In order to give an understanding of the invention I have illustrated inthe drawings a selected. embodiment thereof which will now be describedafter which the novel features will be pointed out in the appendedclaims. Fig. l is a fragmentary plan View of a por said appiicav tion ofthe machine carrying the turret, said view lllustrating the turret andunder thread cutting mechanism;

* Fig. 2 is a somewhat diagrammatic view illustrating the manner inwhich the under thread is drawn into; the thread-receiving notch; i I

Fig. 3 a. plan view of the throat plate with the Under thre retainedtherehyi Fig. 4 a

Inasmuch as the present invent-ion relates simply to the manner ofretaining the under thread at the end of the sewing operation I have notthought it necessary to illustrate a complete sewing machine but haveonly shown asuflicient part of such a machine to enable the invention tohe understood.

' The see 7 tion is a .ied is of the two-thread type it having an upperneedle 1 by which the upper thread 2 is manipulated and it aiso havingunder-thread manipulating devices in the form of ioopers 3 and 4C andloop Spreaders 5 by which the under thread 6 is manipulated. I i

The under-thread handling mechanism is mounted on a tu ret 7 which issituated heeath the work support and which is 1'0- This turret 7 isrotatably mounted in hearings 11 carried by the frame portion 1 of thesewing machine as usualj In some buttonhole sewing machines the frame 12which carries the turret and the stitcl1-for1ning mechanism is movablebaclrand forth on the had portioni18 of the machine to wl 'ch the work10 is clampedfthe to-and-fro motion of the frame 12 carrying thestitching down one side of the huttonliole and back along the other sideof the buttonhole.

The machine herein illustrated is provided with thread-cutting mechanismfor cutting the under thread beneath the work at the end of thesewingfoperation and the thread -cute view of the throatplatea machineto which this men is acted on by 7 thread will ting mechanismillustrated is similar to that shown in my co-pending applicationfie-rial No; 162,890. In this sewing machine when the sewing on thebuttonhole has been compl-eted and the stitch-forming mechanism has beenbrought to rest the frame 12 is given a forward movement or a movementtoward the bottom of Fig. 1thereby to shift the-parts V relatively frombuttonhole sewing position to buttonholescutting position. During thismovement the throat plate 8 will be carried forwardly of that end 14 ofthe buttonhole 15 at which the stitching was completed and a length ofunder thread 6 will be drawn out from the source of supply through thethroat plate 8 as shown by the dotted lines (So in Fig. 2. I

in sewing machines of this type the stitchforming mechanism isfrequently so arranged that when it comes to rest there will be a loop16 of u or thread 2 retained b one of the P loopers of the under threadmechanism and hence when the parts are carried from buttonhole stitchingto buttonhole-cuttmg position there Wlll be a length of under thread 664and also a double length of upper thread 2a extending from the work tothe throat plate shown by dotted lines Fig. 2.

The sewing machine illustrated in the above-mentioned application isprovided with pull-down arms 17, 18 which seize the length of threads2a, 6a and pull them down away from the work from the dotted to the fullline position Fig.2. Said machine is also provided with two cuttingelements 19 and 20 which are carried by pivoted arms 21,

and which at the proper timeare swung from their inoperative positionshown in Fig. 1 into thread-cutting relatlon, thereby. cuttingthethreads 2a, (3a between the throat 8 J and the work and close to thework. 7 r

The parts thus far described are, or may be, all shown and describedinmy abovementioned co-pending application and hence not need to befurther described herein. In accordance with my present invention thethroat 8 is provided with a thread-retain ing notch n3 which has ageneral L shape, it

having the vertical portion 24 extending downwardly from thetop of thethroat plate and then the lateral or horizontal portion 25.

tion of the notch.

the pull-down a'rms17, 18 said e drawn into the vertical por- Thehorizontal portion 25 of the notch has such a dimension that when theturret is turned at the end of the sewing operation to restore it to itsinitial position the under thread 6 will be drawn into said horizontalportion and because of the relatively narrow dimension of thishorizontal portion 25 the thread 6 will be firmly gripped therein asshown in Fig. 3. Hence when the thread cutters, 19 and 20 operate to outthe thread the severed end will be firmly gripped in the portion 25 ofthe thread-receiving notch. This notch so positioned that the portion ofthe thread extending from the notch to the under thread mechanism willbe held in proper position to ensure its being concatenated with theupper thread during the first stitch-forming operation at the beginningof the next seam.

I claim:

1. A sewing machine, having in combination, stitch-forming mechanismcomprising upperand under-thread handling devices, a

turret on which the under-thread handling devices are mounted, a throatplate carried by the turret and having a sewing opening through whichthe under thread passes to the work, and means to cut the under threadbetween the throat plate and the work, said throat plate having athread-receiving notch which is brought into position to receive theunder thread by the turning movement of the turret at the end of theseam.

2. A sewing machine, having in combination, stitch-forming mechanismcomprising upperand under-thread handling devices, a turret on which theunder-thread handling devices are mounted, a throat plate carried by theturret and having a sewing opening through which the under thread passesto the work, means to pull off a length of under thread, and means toout said thread close to the work, said throat plate havinga rightangular thread-gripping notch into which the under thread is forced bythe combined AXEL F. CARLSON.

